Bharatiya Janata Party leader Jaswant Singh Monday sent a fresh letter to Prime Minister Manmohan Singh who had rubbished his claim on the 'mole' in the Prime Minister's Office.

"He (Jaswant Singh) has given a reply to the prime minister's letter," Jaswant Singh's aide told PTI. The letter, the former external affairs minister's second over the 'mole' issue, is a five-six page reply, the aide said, but declined to reveal its contents.

The prime minister had on Sunday shot off a letter to Jaswant Singh following a statement the former union minister had made in Mumbai that the name of the US' 'mole' in the PMO during the Narasimha Rao regime, referred to by him in his book A Call to Honour and other details have been given to Manmohan Singh in his letter sent on July 28.

Singh said Jaswant in his letter did not name the "alleged informant" in the PMO who leaked nuclear secrets to the US and there was no confirmation that the person was from the PMO.